Electrolytic cells are conventionally used to chlorinate water for swimming pools and the like, by decomposing salts such as sodium chloride dissolved therein. In the process of producing chlorine gas, chlorine bubbles form on the cathode of such a cell, and it has been found desirable to wipe such bubbles off the cathode as they are produced, to maximize bare cathode surface area presented to the water and thus facilitate chlorine production. In U.S. Pat. No. 2,530,524 an electrolytic cell is shown with a revolvable electrode and stationary wipers. This device uses alternating current to decompose water, thus causing each electrode in the device to alternately function as cathode and anode. In addition, a monel electrode body is used, this body being subject to deterioration and necessitating the cutting of grooves to insure that an adequate electrode surface area is always presented to the water. The present invention differs radically from that shown in the above mentioned patent in that it has rotatable wiper blades, uses no monel electrode and consequently has no grooves, and uses direct current.